Paraffin control method

ABSTRACT

A method for controlling paraffin deposition in an oil production system and includes injecting an asphaltic crude oil into paraffin base crude oil production and storage facilities. The invention includes the steps of mixing the asphaltic crude oil with the paraffin base crude oil and producing the paraffin base oil to the surface.

United States Patent 2,300,348 10/1942 Dana 166/304X 2,303,823 12/1942Coberly... 252/83 2,765,850 10/1956 Allen l66/304X 3,051,653 8/1962Skolaut et al. 252/83 3,276,519 10/1966 Knox et al 252/8.3X

3,481,870 12/1969 Cheng et a1 166/304X OTHER REFERENCES Reistle, C.E.,Jr.: Paraffin and Congealing-Oil Problems, Bureau of Mines Bulletin 348,US Govt. Printing Office, Washington DC, 1932, pp. 10 and 1 1. Copy in166- 304 Primary Examiner-Stephen J. Novosad Attorneys Eugene S. Coddouand Lee R, Larkin ABSTRACT: A method for controlling paraffin depositionin an oil production system and includes injecting an asphaltic crudeoil into paraffin base crude oil production and storage facilities. Theinvention includes the steps of mixing the asphaltic crude oil with theparaffin base crude oil and producing the paraffin base oil to thesurface.

PARAFFIN CONTROL METHOD BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to a method for preventing parafiindeposition in conveying and storage facilities of paraffin base oil.More particularly, the invention relates to the inhibition of paraffindeposition in an oil well production system by addition of certain waxcrystal modifiers to a production stream of paraffin base oil.

2. Description of the Prior Art In many parts of the world paraffincrude oils exist and are produced with resulting deposition of paraffinin the production tubing, surface lines and tanks. There are variousremedies to inhibit or prevent this deposition, but none have beenentirely satisfactory.

Prior art methods used to solve this problem have been eitherpreventative or curative. Preventative technology includes such methodsas addition of naphthalene and various other solvents or washes to cleanup tubing, rods and pipes when they have become plugged. Such techniqueshave not been universally successful. In recent years some informationhas been published which shows that rods coated with polyethyleneexhibit a resistance to fouling. Several cases have been describedwherein fine particles of polyethylene are injected into the hole toprevent deposition of paraffin in the production tubing.

I-Iot oil treatments and solvents have been used in an attempt to meltparaffin which has been deposited on the interior of lines in theproduction system. Scraping operations have been used to physicallyremove the deposits from piping and storage facilities.

The expense associated with all of the prior art methods becomes verygreat as wells become deeper and the length of the downhole tubingbecomes greater. The cost of chemicals and labor employed in suchoperations in prior arts is extremely burdensome and shows the need foran inexpensive improvement in these procedures.

SUMMARY OF THE INVENTION An object of this invention is to provide animproved method for preventing paraffin deposition in storage andconveying equipment associated with a producing oil well.

Briefly stated, this invention is an improved method for preventingparaffin deposition in a paraffin base crude oil conveying and storingsystem. It includes the steps of injecting an asphaltic crude oil intothe paraffin base crude oil and commingling the asphaltic crude oil withthe paraffin base crude oil. In certain embodiments, the asphaltic crudeoil is injected continuously into the conveying and storage system. Incertain other embodiments the asphaltic crude oil is injectedperiodically in slugs into the conveying and storage system.

In certain other embodiments a method for preventing paraffin depositionin a system for producing paraffin base oil DESCRIPTION OF THE PREFERREDEMBODIMENT production pipe. The presence of the asp altic Oil in theparaffinic oil inhibits the deposition of paraffin during production andstorage. If paraffin deposition has been no problem in the productiontubing from the formation to the wellhead, then the location ofinjection of the asphaltic oil should be at some point upstream ofanticipated or previously observed deposition. The injection of theasphaltic crude oil should inhibit subsequent precipitation of paraffinin any conveying or storage equipment.

It is to be understood that the preferred asphaltic crude oil willproduce no asphaltene precipitate when mixed with the paraffinic stream.7, 7

It is believed that this deposition control is accomplished because of acrystalline state modification of the paraffin by the asphalt or by somespecific physical or chemical property of the asphaltic crude oil. Inother words, some degree of wax crystal modification is accomplished bythe addition of the asphaltic crude oil. Another explanation for thisphenomenon is that the asphaltic oil may act as a polar or film-formingagent on the metal surface in the production and storage equipment.

It is to be understood that the foregoing is generally illustrative ofthe invention, and that other alternatives and embodiments will becomeobvious to one skilled in the art after studying this description. Thedescription, therefore, is to be construed as illustrative only ofcertain embodiments of the invention.

We claim:

1. In a method for preventing paraffin deposition in a paraffin basecrude oil conveying system, the combination of steps comprising:

injecting an asphaltic crude oil into said paraffin base crude oil; and

commingling said asphaltic crude oil with said paraffin base crude oilprior to flowing of said mixture through said system.

2. The invention as claimed in claim 1 wherein; said asphaltic crude oilis a heavy asphaltic Wyoming crude oil.

3. The invention as claimed in claim 1 wherein; said asphaltic crude oilis injected continuously into said conveying system.

4. The invention as claimed in claim 1 wherein; said asphaltic crude oilis injected periodically in slugs into said conveying system.

5. In a method for preventing paraffin deposition in a system forproducing paraffin base oil from an underground formation penetrated bya wellbore, the combination comprising:

conveying an asphaltic crude oil from a storage means to the annulus ofa production pipe situated within said producing underground formation;

injecting said asphaltic crude oil into said paraffin base productionstream;

commingling said added asphaltic crude oil with said paraffin baseproduction stream; and

producing said paraffin base oil stream to the surface.

6. The invention as claimed in claim 5 wherein; said asphaltic crude oilis a heavy asphaltic Wyoming crude oil.

7. The invention as claimed in claim 5 wherein; said injection stepincludes continuously injecting said asphaltic crude oil into saparaffin base production stream.

8. The invention as claimed in claim 5 wherein; said injection stepincludes periodically injecting said asphaltic crude oil into saidparaffin base production stream.

2. The invention as claimed in claim 1 wherein; said asphaltic crude oilis a heavy asphaltic Wyoming crude oil.
 3. The invention as claimed inclaim 1 wherein; said asphaltic crude oil is injected continuously intosaid conveying system.
 4. The invention as claimed in claim 1 wherein;said asphaltic crude oil is injected periodically in slugs into saidconveying system.
 5. In a method for preventing paraffin deposition in asystem for producing paraffin base oil from an underground formationpenetrated by a wellbore, the combination comprising: conveying anasphaltic crude oil from a storage means to the annulus of a productionpipe situated within said producing underground formation; injectingsaid asphaltic crude oil into said paraffin base production stream;commingling said added asphaltic crude oil with said paraffin baseproduction stream; and producing said paraffin base oil stream to thesurface.
 6. The invention as claimed in claim 5 wherein; said asphalticcrude oil is a heavy asphaltic Wyoming crude oil.
 7. The invention asclaimed in claim 5 wherein; said injection step includes continuouslyinjecting said asphaltic crude oil into sa paraffin base productionstream.
 8. The invention as claimed in claim 5 wherein; said injectionstep includes periodically injecting said asphaltic crude oil into saidparaffin base production stream.